Linked from
The 14 pages that link to Intergalactic medium, each with the reason it gives.
Cosmic webRelated: This gas traces and feeds parts of the web that are faint in starlight.
Galactic windRelated: Escaping winds can enrich and heat this gas.
Dispersion measureRelated: Fast radio burst dispersion can reveal electrons outside the Milky Way.
Galaxy filamentRelated: This gas fills filaments alongside galaxies and dark matter.